JP7618131B2 - Copolymer, anti-rust coating composition containing same, dispersant and resist resin - Google Patents

Description

The present invention relates to a copolymer, an anti-rust coating composition containing the same, a dispersant and a resist resin.

Metals such as steel, which is primarily composed of iron, magnesium, aluminum, and titanium, as well as alloys that contain these as their primary components, are widely used as structural materials in a wide range of applications, including marine structures, port facilities, ships, architecture, civil engineering structures, and automobiles, but they suffer from the problem of corrosion when exposed to the natural environment. Structural materials are required to be highly durable, and depending on the usage environment, they need to be able to withstand harsh environments such as exposure to seawater, so various rust prevention treatment methods are used to prevent corrosion.

Chromate treatment and chromate phosphate treatment, which use highly toxic chromium compounds, are commonly used as anti-rust treatment methods, but there is a risk that they will be restricted in the future due to their toxicity. As an alternative method, a method has been proposed in which the metal surface is coated with a polymer to prevent contact with oxygen, moisture, and salt, which cause corrosion.

Examples of monomers that are effective in improving adhesion include monomers with hydroxy groups, such as hydroxyethyl (meth)acrylate and glycerin mono(meth)acrylate, and monomers with carboxy groups, such as acrylic acid and methacrylic acid. Patent Document 1 shows that glycerin monomethacrylate is added as an adhesion improving component.

Furthermore, Patent Document 2 discloses a dental adhesive that has excellent adhesion to dentin and antibacterial effect, and that is a hardening composition containing a gallic acid or tannic acid derivative and a pyrophosphate ester of methacrylic acid, etc.

Dispersion compositions in which organic and inorganic powders are dispersed in a solvent are used in various industrial fields. Examples of organic powders include organic pigments, and dispersion compositions containing organic pigments are used in paints, inks, and color resists. Examples of inorganic powders include ceramic powders and metal powders, and dispersion compositions containing ceramic powders are used in abrasives, fireproof materials, and other electronic components such as dielectric layers of multilayer ceramic capacitors, semiconductor substrates, and various sensors. Dispersion compositions containing metal powders are widely used, for example, as conductive pastes and conductive inks for the electrode layers of multilayer ceramic capacitors and circuit formation materials for substrates.

In recent years, there has been a demand for improved product characteristics, such as miniaturization and higher performance, in electronic component applications. For example, progress has been made in finely granulating the barium titanate in the dielectric layer of multilayer ceramic capacitors to make them smaller and more highly capacitive. In addition, in color resists, progress has been made in increasing the concentration of organic pigments to improve the color reproducibility of liquid crystal displays. Thus, there is a demand for finely granulating various powders and for increasing the concentration of dispersions in dispersion compositions.

When preparing a dispersion composition, dispersibility is often insufficient with the powder alone, so a dispersant is generally used to improve the fluidity and storage stability of the dispersion composition. However, with the microparticulation of the particles, in conventional polymeric dispersants, the dispersant is more likely to cross-link and adsorb between particles, resulting in a decrease in initial dispersibility. In addition, the surface area of the dispersion increases, so the surface free energy of the dispersion increases, making the dispersion system more unstable. Even if the dispersion is dispersed once, the dispersion will aggregate again in an attempt to reduce the apparent surface area of the dispersion, making it difficult to maintain the dispersion state stably. The decrease in initial dispersibility and dispersion stability associated with the microparticulation of the dispersion causes problems such as thickening of the dispersion composition and settling of the dispersion. Dispersion compositions with these problems not only lead to a decrease in productivity, processing characteristics, and handleability, but also lead to a decrease in the quality of the final product.

Therefore, the dispersant is required to have the ability to obtain a dispersion composition that contains a high concentration of dispersing matter and has a low viscosity, as well as the ability to stably disperse the dispersing matter for a long period of time without causing it to settle.

To solve these problems, polymeric dispersants such as those shown in Patent Document 3, such as polyacrylic acid and copolymers thereof, and copolymers of polyoxyalkylene derivatives and maleic anhydride, have been proposed as dispersants.

Photoresist materials are widely used and are essential microfabrication materials in the manufacturing and processing of electronic components, including image display devices such as televisions and image sensors used in digital cameras.

Image display devices and imaging devices have insulating films, color filters, and spacers, which are formed from photoresist materials. With the recent trend toward smaller and finer electronic products, there is a strong demand for improved resist performance. For example, in pigment-dispersed resist compositions used to form color filters, reductions in the resin components in the composition and increases in the pigment concentration have been considered, but these tend to cause a decrease in sensitivity and a decrease in adhesion to the substrate, and therefore there is a demand for improved adhesion to the resist composition.
Furthermore, with the increase in in-vehicle electronic devices and increased overseas transportation, there is a growing demand for adhesion in high temperature and high humidity environments.

As a method for improving adhesion, Patent Document 4 discloses a method of adding a silane coupling agent such as epoxy, (meth)acrylic, or vinyl to a photosensitive resin composition. Furthermore, as a method for improving adhesion at room temperature and also at high temperature and humidity, Patent Document 5 discloses a method of adding an organosilicon compound having a (meth)acrylic or urethane structure.

JP 2014-118508 A Japanese Patent Application Laid-Open No. 7-138119 Patent Publication 2016-222852 Japanese Patent Application Publication No. 10-133370 JP 2018-159930 A

Polymers composed of monomers such as those described in Patent Document 1 have a high adsorption power for metal surfaces, so they exhibit excellent adhesion and provide a certain level of rust prevention. However, when exposed to harsh environments such as the seashore, they cannot completely prevent moisture from coming into contact with the metal surface, and the rust prevention effect is insufficient.

Furthermore, the polymer composed of the monomer as described in Patent Document 2 requires curing by ultraviolet light or heat, and the adhesion and rust prevention effect of the polymer as a coating material to metal substrates are insufficient.
As described above, there is a demand for coating materials that exhibit excellent rust prevention effects even under severe conditions.

However, the dispersant described in Patent Document 3 was not sufficient in terms of obtaining a dispersion composition containing a high concentration of dispersing matter and having a low viscosity, while stably dispersing the dispersing matter for a long period of time without causing it to settle.

Furthermore, when ceramic dielectric layers and metal electrode layers are laminated and fired, as in the case of multilayer ceramic capacitors, the electrode layers and dielectric layers have different shrinkage rates during firing, which can cause defects such as interface peeling, so a method is used in which the same ceramic particles as the dielectric layer, called a co-material, are added to the metal paste. In this case, a method is being considered in which a dispersant for ceramic particles is mixed when preparing the metal paste containing the co-material, but this causes problems such as a decrease in the stability of the metal paste and a decrease in compatibility between dispersants and with other additives such as binder resins, limiting the dispersants that can be used.
For this reason, there has been a demand for a dispersant that has high dispersibility and dispersion stability for metal fine particles and ceramic fine particles even when used alone.

In addition, in the compositions described in Patent Documents 4 and 5, the addition of each component is intended to improve adhesion, but there are concerns that the incorporation of additives may reduce the stability of the composition over time. In addition, in Patent Documents 4 and 5, known compounds are used for the resist resin, which is the main component of the resist resin composition, and the properties of the resist resin are not improved.

An object of the present invention is to provide a novel copolymer that can provide a coating material having excellent rust prevention effect.
Another object of the present invention is to provide a coating material having excellent rust prevention effect.

The object of the present invention is to provide a dispersant that can disperse microparticles in a solvent at a high concentration and provide excellent dispersion stability.

Another object of the present invention is to provide a resist resin that can obtain a pattern with good adhesion even at room temperature and under high temperature and high humidity conditions.

As a result of investigations aimed at solving the above-mentioned problems, the inventors focused on a structure containing adjacent phenolic hydroxyl groups in a polymer, and discovered that the adjacent phenolic hydroxyl groups form a chelate structure with the metal surface, thereby establishing a strong coordinate bond, exhibiting excellent adhesion and excellent rust prevention effects even under harsh conditions, thereby solving the above-mentioned problems.

Furthermore, as a result of investigations aimed at solving the above-mentioned problems, the present inventors focused on a structure containing adjacent phenolic hydroxyl groups in a polymer, and discovered that adjacent phenolic hydroxyl groups exert strong adsorption power on the powder surface by forming a chelate structure or by π-π interactions with aromatic rings, thereby showing excellent initial dispersibility and dispersion stability even for fine particles, thereby solving the above-mentioned problems.
Furthermore, as a result of investigations aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a resist resin comprising a monomer having a specific structure, the monomer having adjacent phenolic hydroxyl groups in the polymer.

（式（１）において、
Ｒは水素原子またはメチル基であり，
Ｘは、炭素数２～５のアルキレン基またはヒドロキシ基を１つ有する炭素数２～５のアルキレン基を示す。） That is, the present invention is as follows.
(1) A copolymer, characterized in that the molar ratio of monomer (A) represented by the following general formula (1) is 1 to 99 mol %, the molar ratio of (meth)acrylic acid alkyl ester (B) having 1 to 22 carbon atoms is 1 to 99 mol %, the molar ratio of other copolymerizable monomer (C) is 0 to 98 mol %, and the weight average molecular weight is 3,000 to 1,000,000.

(In formula (1),
R is a hydrogen atom or a methyl group;
X represents an alkylene group having 2 to 5 carbon atoms or an alkylene group having 2 to 5 carbon atoms and one hydroxyl group.

(2) An anti-rust coating composition comprising the copolymer (1) and an organic solvent.

(3) A dispersant characterized by comprising a copolymer of (1).

（式（２）において、
Ｒ^１は水素原子またはメチル基であり、
Ｒ^２は水素原子または炭素数１～２２のアルキル基であり、
ＯＡは炭素数２～４のオキシアルキレン基であり、
ｎは前記オキシアルキレン基の平均付加モル数であり、１～５０である。） The dispersant according to (3), characterized in that the copolymer is a copolymer containing a constituent component derived from the monomer (C), and the monomer (C) is a (meth)acrylic acid polyoxyalkylene ester represented by the following general formula (2):

(In formula (2),
^R1 is a hydrogen atom or a methyl group;
^R2 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms;
OA is an oxyalkylene group having 2 to 4 carbon atoms;
n is the average number of moles of the oxyalkylene group added, which is 1 to 50.

(5) A dispersion composition comprising a dispersant (3) or (4), a solvent, and a dispersion dispersed by the dispersant.

(6) A resist resin comprising the copolymer of (1),
a molar ratio of the monomer (A) is 1 to 40 mol %, a molar ratio of the (meth)acrylic acid alkyl ester (B) is 1 to 94 mol %, the other monomers (C) contain at least a monomer (C1) having a carboxyl group, a molar ratio of the monomer (C1) having a carboxyl group is 5 to 40 mol %, a molar ratio of a copolymerizable monomer (C2) other than the monomer (C1) having a carboxyl group is 0 to 93 mol %, and a weight average molecular weight is 3,000 to 100,000.

The copolymer of the present invention is a novel copolymer containing a monomer having a specific structure containing adjacent phenolic hydroxyl groups. Since these adjacent phenolic hydroxyl groups are strongly coordinated to the metal surface, an anti-rust coating composition containing this copolymer can impart an excellent anti-rust effect to metals. As a result, metal materials using the anti-rust coating composition of the present invention have excellent durability due to their high anti-rust effect.

According to the invention of the dispersion composition of the present invention, it is possible to disperse fine particle dispersions, such as organic or inorganic powders having a particle diameter of 1 μm or less, in a solvent at high concentrations and to impart excellent dispersion stability.

The resist resin of the present invention makes it possible to obtain a resin film with good adhesion even at room temperature and under high temperature and humidity conditions.

Hereinafter, an embodiment of the present invention will be described.
[Monomer (A)]
The monomer (A) used in the present invention is represented by the following general formula (1).

In formula (1), R is a hydrogen atom or a methyl group, and from the viewpoints of the stability of the monomer and ease of polymerization, a methyl group is particularly preferred.
X represents an alkylene group having 2 to 5 carbon atoms or an alkylene group having 2 to 5 carbon atoms and one hydroxyl group. The alkylene group having one hydroxyl group has a carbon chain of the alkylene group and one hydroxyl group on the carbon chain. From the viewpoint of hydrophilicity and ease of synthesis, X is preferably an alkylene group having one hydroxyl group, and more preferably X has 2 to 4 carbon atoms, and particularly preferably X has 3 carbon atoms. The substitution position of the hydroxyl group on the alkylene group is preferably the 2-position or 3-position, and more preferably the 2-position. Specific examples of X include an ethylene group, a propylene group, a butylene group, a pentylene group, a 1-hydroxyethylene group, a 2-hydroxypropylene group, a 2-hydroxybutylene group, a 3-hydroxybutylene group, a 2-hydroxypentylene group, and a 3-hydroxypentylene group.
The substitution position on the benzene ring of XOC(O)-- is the 4- or 5-position on the benzene ring, but from the viewpoint of availability of raw materials, a structure derived from gallic acid at the 5-position is particularly preferred.
The monomer (A) may be used alone or in combination of two or more kinds.

When the total monomers constituting the copolymer are taken as 100 mol%, the molar ratio of monomer (A) is 1 mol% or more. If the molar ratio of monomer (A) is too low, there is a risk of reduced adhesion, so it is set to 5 mol% or more, preferably 7 mol% or more, and more preferably 10 mol% or more.

When all the monomers constituting the copolymer are taken as 100 mol %, the molar ratio of the monomer (A) is 99 mol % or less.
From the viewpoint of ease of polymerization, the molar ratio of the monomer (A) is preferably 50 mol % or less, more preferably 40 mol % or less, and particularly preferably 30 mol % or less.

(Monomer (B))
The monomer (B) used in the present invention is a (meth)acrylic acid alkyl ester having 1 to 22 carbon atoms.
The alkyl chain length of the (meth)acrylic acid alkyl ester is from 1 to 22 carbon atoms, and from the viewpoint of dispersibility and solubility in various solvents, the alkyl chain length is preferably from 2 to 22 carbon atoms, and more preferably from 4 to 18 carbon atoms. For example, examples of the (meth)acrylic acid ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate. Of these, linear alkyl groups such as butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, and stearyl (meth)acrylate are preferred, butyl (meth)acrylate or stearyl (meth)acrylate is more preferred, and butyl (meth)acrylate is even more preferred.

In the case of dispersants, the alkyl chain length of the (meth)acrylic acid alkyl ester is 1 to 22 carbon atoms, and from the viewpoint of adhesiveness and the glass transition point of the copolymer, 1 to 12 carbon atoms is preferable, and 2 to 10 carbon atoms is more preferable. Examples of the (meth)acrylic acid ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate, and ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate are preferred.

In the case of a resist resin, the aliphatic alkyl chain of the (meth)acrylic acid alkyl ester has an alkyl chain length of 1 to 22 carbon atoms, and from the viewpoints of adhesiveness and the glass transition point of the polymer, the alkyl chain length preferably has 1 to 12 carbon atoms, more preferably has 1 to 8 carbon atoms, even more preferably has 1 to 4 carbon atoms, and particularly preferably has 1 carbon atom. Examples of the (meth)acrylic acid ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate. Of these, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate are preferred, and methyl (meth)acrylate is more preferred.
The alicyclic alkyl chain of the (meth)acrylic acid alkyl ester has an alkyl chain length of 6 to 12 carbon atoms, and from the viewpoints of heat resistance and chemical resistance, the alkyl chain length is preferably 6 to 10 carbon atoms, and more preferably 6 carbon atoms. Examples of the alicyclic (meth)acrylic acid ester monomer include cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, and dicyclopentanyl (meth)acrylate, with cyclohexyl (meth)acrylate being preferred.

The monomer (B) may be used alone or in combination of two or more kinds.
When the total monomers constituting the copolymer are taken as 100 mol%, the molar ratio of the monomer (B) is 1 mol% or more. If the molar ratio of the monomer (B) is too low, the solubility in the solvent may decrease, so the molar ratio is 1 mol% or more, preferably 10 mol% or more, and more preferably 20 mol% or more. The molar ratio of the monomer (B) is 99 mol% or less, but from the viewpoint of dispersibility, it is preferably 70 mol% or less, and more preferably 30 mol% or less.
In the case of a dispersant, when the total monomers constituting the copolymer are taken as 100 mol %, the molar ratio of monomer (B) is 1 mol % or more. If the molar ratio of monomer (B) is too low, there is a risk of reduced adhesion, so the molar ratio is 1 mol % or more, preferably 50 mol % or more, and more preferably 65 mol % or more.

(Monomer (C))
The other monomer (C) copolymerizable with the monomer (A) and the monomer (B) is not particularly limited as long as it is a monomer copolymerizable with the monomer (A) and the monomer (B), and one or more types may be included. However, (meth)acrylic acid esters other than (meth)acrylic acid alkyl esters, aromatic vinyl compounds, and acrylamide compounds are preferred.

Examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, t-butylstyrene, chlorostyrene, hydroxystyrene, t-butoxystyrene, vinyltoluene, and vinylnaphthalene, with styrene being preferred from the standpoint of polymerizability.

Examples of acrylamide compounds include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, (meth)acryloylmorpholine, etc., with (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide being preferred.

Examples of (meth)acrylic acid ester monomers other than (meth)acrylic acid alkyl esters include phenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glyceryl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and alkylene oxide adducts of (meth)acrylic acid. From the viewpoint of improving affinity for metal surfaces and hydrophilicity, preferred are 2-hydroxyethyl (meth)acrylate and glyceryl (meth)acrylate.
In the case of a dispersant, the molar ratio of the monomer (C) is set to 0 to 98 mol %, but from the viewpoints of dispersibility and solvent solubility, it is preferably set to 10 to 70 mol %, and more preferably 50 to 70 mol %.

（式（２）において、
Ｒ^１は水素原子またはメチル基であり、
Ｒ^２は水素原子または炭素数１～２２のアルキル基であり、
ＯＡは炭素数２～４のオキシアルキレン基であり、
ｎは前記オキシアルキレン基の平均付加モル数であり、１～５０である。） Among the monomers (C), a (meth)acrylic acid polyoxyalkylene ester represented by the following general formula (2) is preferred.

(In formula (2),
^R1 is a hydrogen atom or a methyl group;
^R2 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms;
OA is an oxyalkylene group having 2 to 4 carbon atoms;
n is the average number of moles of the oxyalkylene group added, which is 1 to 50.

The number of moles of the oxyalkylene group added in the (meth)acrylic acid polyoxyalkylene ester is 1 to 50, preferably 3 to 30 from the viewpoint of dispersibility and polymerizability, and more preferably 5 to 20. The moiety represented by R2 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, preferably a hydrogen atom or a carbon number of 1 to 18 from the viewpoint of affinity to the solvent or the dispersed substance, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom. Examples of the oxyalkylene group include an oxyethylene group, an oxypropylene group, and an oxybutylene group, and from the viewpoint of controlling hydrophobicity and hydrophilicity, an oxyethylene group and an oxypropylene group are preferred. One or more of these oxyalkylene groups may be included, and when two or more types are included, the structure may be a random structure or a block structure.

(Monomer (C1))
The monomer (C1) having a carboxyl group is a monomer having one or more carboxyl groups in the molecule. The number of carboxyl groups in the monomer (C1) is more preferably one. Specific examples of the monomer (C1) include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, etc., and acrylic acid and methacrylic acid are preferred in terms of copolymerization reactivity, solubility in an alkaline aqueous solution, and ease of availability. The monomer (C1) may be used alone or in combination of two or more kinds.

(Monomer (C2))
The other copolymerizable monomer (C2) is not particularly limited as long as it is a monomer copolymerizable with the monomers (A), (B), and (C1), and may contain one or more types. However, (meth)acrylic acid esters other than (meth)acrylic acid alkyl esters and aromatic vinyl compounds are preferred.

Examples of (meth)acrylic acid ester monomers other than (meth)acrylic acid alkyl esters include phenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glyceryl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and ethylene oxide adducts of (meth)acrylic acid, with benzyl (meth)acrylate being preferred. From the viewpoint of developability, 2-hydroxyethyl (meth)acrylate, glyceryl (meth)acrylate, and hydroxypropyl (meth)acrylate are preferred.

Examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, t-butylstyrene, chlorostyrene, hydroxystyrene, t-butoxystyrene, vinyltoluene, and vinylnaphthalene, with styrene being preferred.

[Molecular weight of copolymer]
The weight average molecular weight of the copolymer of the present invention can be determined in terms of polystyrene using gel permeation chromatography (GPC) and is preferably 10,000 to 500,000, more preferably 20,000 to 100,000. If the weight average molecular weight of the copolymer is too low, the coating film becomes brittle and the rust prevention effect decreases, whereas if the weight average molecular weight is too high, there is a risk of a decrease in solvent solubility or coatability due to increased viscosity.

[Molecular weight of copolymer constituting dispersant]
The weight average molecular weight of the copolymer constituting the dispersant of the present invention can be determined in terms of polystyrene using gel permeation chromatography (GPC), and is preferably 3,000 to 800,000, more preferably 5,000 to 50,000, and even more preferably 10,000 to 30,000. If the weight average molecular weight of the copolymer is too low or too high, dispersibility may decrease.

[Molecular weight of resist resin]
The weight average molecular weight of the resist resin can be determined in terms of polystyrene using gel permeation chromatography (GPC), and is 3,000 to 100,000, preferably 4,000 to 50,000, and more preferably 5,000 to 30,000. If the weight average molecular weight of the resist resin is too low, the adhesion may be insufficient, and if the weight average molecular weight is too high, the resist properties such as developability may deteriorate.

(Ratio of monomers in resist resin)
When the total amount of the monomers (A), (B), (C1), and (C2) constituting the polymer is taken as 100 mol %, the content of the monomer (A) is 1 to 40 mol %, preferably 3 to 30 mol %, more preferably 5 to 30 mol %, and particularly preferably 5 to 20 mol %.

When the total amount of the monomers (A), (B), (C1), and (C2) constituting the polymer is taken as 100 mol %, the content of the monomer (B) is 1 to 94 mol %, preferably 5 to 90 mol %, and more preferably 10 to 85 mol %.
When the total amount of the monomers (A), (B), (C1) and (C2) constituting the polymer is taken as 100 mol %, the content of the monomer (C1) is 5 to 40 mol %, preferably 7 to 30 mol %, and more preferably 10 to 20 mol %.

When the total amount of the monomers (A), (B), (C1) and (C2) constituting the polymer is taken as 100 mol %, the content of the other copolymerizable monomer (C2) is 0 to 93 mol %. By setting the content of the monomers (A) to (C2) at the above-mentioned ratio, a resin film with good adhesion can be obtained even at room temperature and under high temperature and high humidity conditions.

[Method for producing monomer (A)]
Monomer (A) of the present invention is a monomer having three adjacent hydroxy groups on a benzene ring.
The monomer (A) can be obtained, for example, by addition reaction of a compound having three adjacent hydroxy groups and a carboxylic acid on a benzene ring with a compound having a (meth)acryloyl group and an epoxy group, and examples of the monomer (A) include monomers having a structure shown in the following formula (3).

Examples of the compound having three adjacent hydroxy groups and a carboxylic acid on the benzene ring include gallic acid and 2,3,4-trihydroxybenzoic acid, with gallic acid being preferred from the viewpoint of ease of availability. Examples of the compound having a (meth)acryloyl group and an epoxy group include glycidyl (meth)acrylate, with glycidyl methacrylate being preferred from the viewpoint of ease of synthesis of monomer (A).

The reaction can be carried out by mixing the two, raising the temperature as required, and using a known method. If necessary, a catalyst may be added.
As for the reaction conditions, the temperature is preferably 50 to 150° C., and more preferably 70 to 110° C. If the temperature is too low, the reaction may not proceed sufficiently, whereas if the temperature is too high, gelation may occur.

The addition reaction may be carried out using a catalyst. Any known catalyst may be used, but tertiary amines, quaternary ammonium salts, organic phosphorus, organometallic catalysts, metal oxides, and metal hydroxides are preferred, and more preferred than tertiary amines and quaternary ammonium salts. Examples include tertiary amines such as triethylamine, tributylamine, and N,N-dimethylbutylamine, and quaternary ammonium salts such as tetrabutylammonium bromide, tetrabutylammonium chloride, trimethylbenzylammonium chloride, and triethylbenzylammonium chloride.

The amount of catalyst used is preferably 0.01 to 30% by mass, more preferably 0.1 to 15% by mass, based on the compound having a phenolic hydroxyl group. If too little catalyst is used, the reaction may not proceed sufficiently, and if too much catalyst is used, there is a risk of discoloration.

In addition, during the reaction, a gas having a polymerization inhibitory effect may be introduced into the reaction system, or a polymerization inhibitor may be added. For example, the gas may be air, and the polymerization inhibitor may be hydroquinone, methoquinone, 2,6-di-t-butylphenol, etc. These inhibitors may be used alone or in combination of two or more. The amount of inhibitor used is preferably 0.01 to 3% by mass, more preferably 0.04 to 1% by mass, based on the compound having a (meth)acryloyl group and an epoxy group. When a gas having a polymerization inhibitory effect is introduced into the reaction system, it may be dehydrated with a drying agent such as silica gel. In addition, structural isomers are generated in this reaction, but they may be used after isolation or as a mixture of isomers.

The above reaction may be carried out in the presence of a solvent, for example, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, toluene, xylene, methanol, ethanol, tetrahydrofuran, dioxane, or the like.
The monomer obtained by the above reaction may be used as it is, or may be purified by a known method such as crystallization or crystallization.

[Method for producing copolymer]
Next, the method for producing the copolymer of the present invention will be described.
The copolymer of the present invention can be obtained by radical polymerization of a mixture of a plurality of necessary monomers. The polymerization can be carried out by a known method. For example, solution polymerization, suspension polymerization, emulsion polymerization, etc. can be mentioned, but solution polymerization and suspension polymerization are preferred in terms of being easy to adjust the weight average molecular weight of the copolymer within the above range.

The polymerization initiator may be a known one. For example, di(4-t-butylcyclohexyl)peroxydicarbonate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, and other organic peroxides, and 2,2'-azobisisobutyronitrile, and other azo polymerization initiators may be used. These polymerization initiators may be used alone or in combination of two or more.
The amount of the polymerization initiator used can be appropriately set depending on the combination of monomers used, reaction conditions, and the like.

When adding the polymerization initiator, for example, the entire amount may be charged at once, or a portion may be charged at once and the remainder may be added dropwise, or the entire amount may be added dropwise. It is preferable to add the polymerization initiator dropwise together with the monomer, since this makes it easier to control the reaction, and it is also preferable to add the polymerization initiator after the monomer has been added dropwise, since this reduces the amount of residual monomer.

The polymerization solvent used in solution polymerization can be one in which the monomer and polymerization initiator are soluble, and specific examples include methanol, ethanol, 2-propanol, acetone, toluene, methyl ethyl ketone, and propylene glycol monomethyl ether.

The concentration of the monomers (total amount) relative to the polymerization solvent is preferably 10 to 70% by mass, more preferably 10 to 60% by mass, and particularly preferably 20 to 50% by mass. If the concentration of the monomer mixture is too low, the monomers tend to remain, and the molecular weight of the resulting copolymer may decrease, whereas if the monomer concentration is too high, it may become difficult to control heat generation.
When the monomer is added, for example, the entire amount may be added at once, a part of the monomer may be added at once and the rest may be added dropwise, or the entire amount may be added dropwise. From the viewpoint of ease of controlling heat generation, it is preferable to add a part of the monomer at once and the rest may be added dropwise, or to add the entire amount dropwise.

The polymerization temperature depends on the type of polymerization solvent, and is, for example, 50°C to 110°C. The polymerization time depends on the type of polymerization initiator and the polymerization temperature. For example, when di(4-t-butylcyclohexyl)peroxydicarbonate is used as the polymerization initiator, a polymerization time of about 6 hours is appropriate when the polymerization temperature is 70°C.

By carrying out the above polymerization reaction, the copolymer according to the resin composition of the present invention is obtained. The obtained copolymer may be used as it is, or the reaction liquid after the polymerization reaction may be filtered or purified to isolate it.

[Anti-rust coating composition]
The copolymer of the present invention is particularly suitable as an anti-rust coating composition. In addition to the copolymer of the present invention, the anti-rust coating composition may contain a solvent and, if necessary, other components such as a rust inhibitor and an antioxidant.

Examples of solvents include hydrocarbon solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, 1-butanol, and diacetone alcohol, ether solvents such as diethyl ether and tetrahydrofuran, glycol ether solvents such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether, glycol ether acetate solvents such as diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and propylene glycol monomethyl ether acetate, terpineol solvents such as terpineol, dihydroterpineol, and dihydroterpineol acetate, and ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. These can be used alone or in combination of two or more.

The copolymer content in the anti-rust coating composition is preferably 5 to 80% by weight, more preferably 10 to 50% by weight.

Dispersion Composition
The dispersion composition of the present invention contains a dispersant, a dispersion, and a solvent.
Here, the total mass of the dispersant, dispersion and solvent is 100% by mass. In this case, the content of the dispersant is preferably 0.05 to 20% by mass. If the content of the dispersant is less than 0.05% by mass, sufficient initial dispersibility and dispersion stability may not be obtained, and even if the content exceeds 20% by mass, an effect commensurate with the content may not be obtained. From the viewpoint of initial dispersibility and dispersion stability, the content of the dispersant is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass.

The dispersion contained in the dispersion composition of the present invention may be an organic powder or an inorganic powder.
Examples of the organic powder include organic pigments such as azo, diazo, condensed azo, thioindigo, indathrone, quinacridone, anthraquinone, benzimidazolone, phenylene, phthalocyanine, anthrapyridine, and dioxazine.

Examples of inorganic powders include metal powders such as iron, aluminum, chromium, nickel, cobalt, zinc, tungsten, indium, tin, palladium, zirconium, titanium, copper, silver, gold, and platinum; alloy powders consisting of two or more types of metals or metals and non-metals; composite powders made by combining metal powders or alloy powders; and mixed powders consisting of two or more types of inorganic powders or inorganic powders mixed with other powders.

Other examples of inorganic powders include powders of silicate minerals, other silicate compounds, carbonate compounds, sulfate compounds, hydroxide compounds, oxide compounds, nitride compounds, carbide compounds, titanate compounds, etc. Examples of inorganic powders include powders of kaolin, clay, talc, mica, bentonite, dolomite, calcium silicate, aluminum silicate, magnesium silicate, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, aluminum sulfate, aluminum hydroxide, iron hydroxide, zirconium oxide, magnesium oxide, aluminum oxide, titanium oxide, iron oxide, zinc oxide, antimony trioxide, indium oxide, indium tin oxide, silicon carbide, tungsten carbide, aluminum nitride, silicon nitride, boron nitride, barium titanate, calcium titanate, strontium titanate, carbon black, glass fiber, carbon fiber, carbon nanofiber, and carbon nanotubes (single-wall nanotubes, double-wall nanotubes, and multi-wall nanotubes).

Preferred dispersions are metal powders such as nickel, cobalt, palladium, copper, silver, gold, and platinum; powders of oxide compounds such as zirconium oxide, magnesium oxide, aluminum oxide, iron oxide, zinc oxide, and indium tin oxide; and powders of titanate compounds such as barium titanate, calcium titanate, and strontium titanate.

From the viewpoint of usefulness, the average particle size of the dispersion is preferably 0.01 to 1 μm, more preferably 0.01 to 0.7 μm, and particularly preferably 0.01 to 0.5 μm. The average particle size of the dispersion can be measured by electron microscopy using a SEM (scanning electron microscope) or a TEM (transmission electron microscope) or by the microtrack method (laser diffraction/scattering method).

When the total amount of the dispersant, dispersion and solvent is taken as 100% by mass, the content of the dispersion in the dispersion composition is typically 10 to 90% by mass, preferably 30 to 85% by mass, and more preferably 55 to 80% by mass.

Examples of the solvent (organic solvent) that serves as a dispersion medium for dispersing the dispersion in the dispersion composition of the present invention include aromatic hydrocarbon solvents such as toluene and xylene, hydrocarbon solvents such as cyclohexane, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ester solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and γ-butyrolactone, glycol ether solvents such as ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol mono n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, and dipropylene glycol mono n-butyl ether, and ethylene glycol mono ethyl ether solvents such as ethylene glycol mono n-butyl ether, dipropylene glycol mono n-butyl ether, dipropylene glycol mono n-butyl ether, dipropylene glycol mono n-butyl ether, and dipropylene glycol mono n-butyl ether. Cholesterol monoethyl ether acetate, ethylene glycol monoisopropyl acetate, ethylene glycol mono n-butyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono n-propyl ether acetate, propylene glycol mono n-butyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol mono n-propyl ether acetate, and glycol ether ester solvents such as dipropylene glycol mono n-butyl ether acetate; terpene solvents such as terpineol, dihydroterpineol, terpinyl acetate, and dihydroterpinyl acetate; and alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and t-butanol. One or more solvents selected from these solvents can be used.
The content of the solvent in the dispersion composition is usually 5 to 50% by mass, preferably 10 to 40% by mass, and more preferably 10 to 30% by mass.

The dispersion composition of the present invention may contain various additives such as other surfactants, binders, plasticizers, and defoamers, provided that the purpose of the composition is not impaired.

The dispersion composition of the present invention can be produced in accordance with known methods for producing dispersion compositions. For example, a method of adding a dispersion to a solvent in which the dispersion is dissolved, and then stirring and mixing at room temperature, a method of adding a solvent and a dispersant to the dispersion, and then stirring and mixing at room temperature, etc. can be mentioned.

As a dispersing device for stirring, mixing, or dispersing, a known dispersing machine can be used. Examples include a roll mill, ball mill, bead mill, sand mill, homogenizer, disperser, and rotation-revolution type mixer. Dispersion treatment can also be performed in an ultrasonic bath.

[Resist resin composition]
The resist resin of the present invention may be used as a resist resin composition comprising a photopolymerization initiator, a polymerizable compound, and a solvent.
The photopolymerization initiator is a compound that becomes the starting point of the polymerization reaction of the polymerizable compound by irradiation with light, and any known photopolymerization initiator can be used. The wavelength is not particularly limited, but an initiator type suitable for the wavelength can be selected and used. The photopolymerization initiator in the present invention can be used alone or in combination of two or more kinds.

Examples of the photopolymerization initiator of the present invention include aromatic ketones such as benzophenone, N,N'-tetraalkyl-4,4'-diaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone; quinones such as alkylanthraquinone and phenanthrenequinone; benzoin compounds such as benzoin and alkylbenzoin; benzoin ether compounds such as benzoin alkyl ether and benzoin phenyl ether; benzyl derivatives such as benzyl dimethyl ketal; 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxy ... 2,4,5-triarylimidazole dimers such as 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer; N-phenylglycine; and N-phenylglycine derivatives. Examples of compounds that can be used include acridine derivatives such as 9-phenylacridine, oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], coumarin compounds such as 7-diethylamino-4-methylcoumarin, thioxanthone compounds such as 2,4-diethylthioxanthone, and acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.
The content of the photopolymerization initiator is preferably 0.01% by mass to 50% by mass, more preferably 0.1% by mass to 40% by mass, and further preferably 0.1% by mass to 30% by mass, based on the total solid content of the photosensitive resin composition.

The polymerizable compound is a compound having at least one polymerizable functional group, and any known compound can be used.
Examples of the polymerizable compound include 2-hydroxyethyl (meth)acrylate, carbitol (meth)acrylate, isobornyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ) acrylate, glycerin di(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. are preferred, and compounds having two or more polymerizable functional groups may be used in combination.

The content of the polymerizable compound is preferably 3% by mass to 200% by mass, more preferably 5% by mass to 150% by mass, and even more preferably 10% by mass to 100% by mass, relative to the total solid content of the photosensitive resin composition.

As the solvent, any known solvent may be used, and two or more of them may be used in combination. Examples of the solvent include methyl alcohol, ethyl alcohol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, N,N-dimethylformamide, tetrahydrofuran, benzene, toluene, methoxyethoxyethanol, ethoxyethoxyethanol, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, 2-methoxyethyl acetate, and propylene glycol monomethyl ether acetate.
Other components such as a leveling agent can be added to the resist resin composition as long as they do not impair the effects of the present invention.

[Examples of copolymers and rust-preventive compositions]
(Synthesis of Monomer)
Ethanol (Kishida Chemical Co., Ltd.), 50.0 g of gallic acid monohydrate (Tokyo Chemical Industry Co., Ltd.), and 2.4 g of triethylamine were charged into a 1 L flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel, and 51.3 g of glycidyl methacrylate (product name: Blenmar GH (NOF Corp.)) was added dropwise from the dropping funnel over 30 minutes, and the reaction was carried out at 80° C. for 10 hours. 100 g of butyl acetate (Kishida Chemical Co., Ltd.) was added to the reaction solution, and the solution was washed successively with a 0.1 M aqueous solution of sodium bicarbonate and saturated saline. The butyl acetate layer after washing was concentrated to obtain a monomer having the structure shown in the following formula (3).

Example 1
In a 1 L separable flask equipped with a stirrer, a thermometer, a condenser and a nitrogen inlet tube, 150 g of isopropanol (Kishida Chemical Co., Ltd.), 11.0 g of monomer (A), 4 g of glycerin monomethacrylate (product name: Blenmer GLM (NOF Corp.)), and 85 g of 2-ethylhexyl methacrylate (Tokyo Chemical Industry Co., Ltd.) were charged, and the atmosphere in the flask was replaced with nitrogen to create a nitrogen atmosphere. Thereafter, 0.5 g of 2,2'-azobis(2,4-dimethylvaleronitrile) (product name: V-65 (Wako Pure Chemical Industries, Ltd.)) was added, and the mixture was heated to 75°C and reacted for 3 hours to obtain an isopropanol solution of copolymer A. The solvent was then removed over 180 minutes at 60°C under reduced pressure to obtain the copolymer of Example 1.

Example 2
A copolymer of Example 2 was obtained in the same manner as in Example 1, except that the amounts of the monomer (A) used were changed to 13 g, glycerin monomethacrylate to 5 g, and ethylhexyl methacrylate to 82 g.

Example 3
A copolymer of Example 3 was obtained in the same manner as in Example 1, except that 30 g of monomer (A), 0 g of glycerin monomethacrylate, and 70 g of ethylhexyl methacrylate were used.

Example 4
The copolymer of Example 4 was obtained in the same manner as in Example 1, except that 13 g of monomer (A), 5 g of glycerin monomethacrylate, and 82 g of methyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of ethylhexyl methacrylate.

(Example 5)
The copolymer of Example 5 was obtained in the same manner as in Example 1, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) used was changed from 0.5 g to 0.1 g.

Example 6
The copolymer of Example 6 was obtained in the same manner as in Example 1, except that the amounts of the monomer (A) and ethylhexyl methacrylate used were 5 g and 95 g, respectively.

(Polymerization Example 7)
The copolymer of Example 7 was obtained in the same manner as in Example 1, except that the amount of monomer (A) used was 11 g, the amount of glycerin monomethacrylate used was 4 g, and styrene was used in place of ethylhexyl methacrylate at 85 g.

(Comparative Example 1)
A copolymer of Comparative Example 1 was obtained in the same manner as in Example 1, except that the amount of the monomer (A) used was 0 g and the amount of ethylhexyl methacrylate used was 100.0 g.

(Comparative Example 2)
A copolymer of Comparative Example 2 was obtained in the same manner as in Example 4, except that the amounts of the monomer (A) used were 0 g, ethylhexyl methacrylate was 90 g, and glycerin monomethacrylate was 10 g.

[Adhesion test]
A glass substrate (26mm x 76mm) was washed with ethanol, hexane, and acetone, and various copolymer solutions dissolved in tetrahydrofuran (THF) were applied to the substrate at 1.2mg/ ^cm2 and dried at room temperature for 12 hours. The test was performed by the cross-cut method (JIS-K5600-5-6 adhesion, 1mm intervals).
Evaluation criteria: ◎: No peeling ○: Peeling of 4 squares or less ×: Peeling of 5 squares or more

[Rust prevention test]
The dissolved copolymer was applied to a steel substrate (SPCC-SD 1mm x 25mm x 100mm) to a thickness of 0.8mg/ ^cm2 , and dried at room temperature for 12 hours to prepare a sample piece. The sample piece was immersed in a 3.5% NaCl aqueous solution and visually inspected for the presence of rust and changes in the coating.
Evaluation criteria ◎: No rusting ○: Rust is present on less than 10% of the surface area ×: Rust is present on 10% or more of the surface area

[Smoothness test]
The dissolved copolymer was applied to a steel substrate (SPCC-SD 1mm x 25mm x 100mm) to a thickness of 0.8mg/ ^cm2 , and then dried at room temperature for 12 hours to prepare a sample piece. The prepared coating film was visually observed, and the smoothness was evaluated based on the presence or absence of surface defects.
Evaluation criteria: ◎: No defects are observed. 〇: Slight defects are observed. ×: Clear defects are observed.

As shown in Table 1, Examples 1 to 7 were excellent in all respects of adhesion, rust prevention, and smoothness.
On the other hand, in Comparative Example 1, the copolymer did not contain the monomer (A), but the adhesion and rust prevention were low. Also, in Comparative Example 2, the copolymer did not contain the monomer (A), but the rust prevention and smoothness were low.

Dispersion Composition Examples
(Synthesis of Monomer)
Ethanol (Kishida Chemical Co., Ltd.), 50.0 g of gallic acid monohydrate (Tokyo Chemical Industry Co., Ltd.), and 2.4 g of triethylamine were charged into a 1 L flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel, and 51.3 g of glycidyl methacrylate (product name: Blenmar GH (NOF Corp.)) was added dropwise from the dropping funnel over 30 minutes, and the reaction was carried out at 80° C. for 10 hours. 100 g of butyl acetate (Kishida Chemical Co., Ltd.) was added to the reaction solution, and the mixture was washed successively with a 0.1 M aqueous solution of sodium bicarbonate and saturated saline. The butyl acetate layer after washing was concentrated to obtain a monomer mainly composed of the structure shown in the following formula (3).

(Polymerization example 1: copolymer A)
Into a 1 L separable flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen inlet tube, 400 g of isopropanol (Kishida Chemical Co., Ltd.), 10.0 g of monomer (A), butyl methacrylate (Tokyo Chemical Industry Co., Ltd.), 20.0 g of 2,2'-azobis( 3.0 g of 2,4-dimethylvaleronitrile (product name: V-65 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added, the temperature was raised to 75° C., and the mixture was allowed to react for 3 hours to obtain an isopropanol solution of copolymer A. The solvent was then removed at 60° C. under reduced pressure for 180 minutes to obtain Copolymer A.

(Polymerization example 2: copolymer B)
Copolymer B was obtained in the same manner as in Polymerization Example 1, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) used was changed from 3.0 g to 1.0 g.

(Polymerization Example 3: Copolymer C)
Copolymer C was obtained in the same manner as in Polymerization Example 1, except that the amount of the monomer (A) was 20.0 g and the amount of the polypropylene glycol monomethacrylate was 60.0 g.

(Polymerization Example 4: Copolymer D)
Copolymer D was obtained in the same manner as in Polymerization Example 1, except that the amount of the monomer (A) was 50.0 g and the amount of the polypropylene glycol monomethacrylate was 30.0 g.

(Polymerization Example 5: Copolymer E)
Copolymer E was obtained in the same manner as in Polymerization Example 1, except that methoxypolyethylene glycol monomethacrylate (BLEMMER PME-400, manufactured by NOF Corp.) was used instead of polypropylene glycol monomethacrylate.

(Polymerization Example 6: Copolymer F)
Copolymer F was obtained in the same manner as in Polymerization Example 1, except that stearyl methacrylate (Blemmer SMA, manufactured by NOF Corp.) was used instead of polypropylene glycol monomethacrylate.

(Polymerization Example 7: Copolymer G)
Copolymer G was obtained in the same manner as in Polymerization Example 1, except that the amounts of Monomer (A) used were 0 g and 100.0 g of polypropylene glycol monomethacrylate were used.

(Polymerization Example 8: Copolymer H)
Copolymer H was obtained in the same manner as in Polymerization Example 1, except that the amount of the monomer (A) used was 0 g and the amount of the methoxypolyethylene glycol monomethacrylate used was 100.0 g.

(Evaluation of Barium Titanate Dispersibility)
20.0 g of barium titanate powder (average particle size: 0.1 μm, measured by electron microscopy using SEM), 5.0 g of toluene/ethanol mixed solvent (3/7, mass ratio), and 0.4 g of dispersant were weighed into a 50 mL screw tube, and pre-dispersed by stirring for 5 minutes with a planetary centrifugal mixer. After that, the mixture was dispersed for 3 hours with 1.0 mm zirconia beads in a bead mill to obtain a slurry-like dispersion composition.
For each dispersion composition, the shear viscosity was measured at a temperature of 25° C. and a shear rate of 0.1 to 100 (1/s) using a dynamic viscoelasticity measuring device (Paar Physica MCR-302, manufactured by Anton Paar).

◎: Viscosity at 3s-1 is 10 Pa・s or less. 〇: Viscosity at 3s-1 is less than 500 Pa・s. ×: Viscosity at 3s-1 is 500 Pa・s or more.

(Nickel dispersion evaluation)
20.0 g of nickel powder (average particle size: 0.1 μm, measured by electron microscopy using SEM), 5.0 g of dihydroterpineol, and 0.2 g of dispersant were weighed into a 50 mL screw tube and stirred for 5 minutes with a planetary centrifugal mixer to obtain a slurry-like dispersion composition.
For each dispersion composition, the shear viscosity was measured at a temperature of 25° C. and a shear rate of 0.1 to 100 (1/s) using a dynamic viscoelasticity measuring device (Paar Physica MCR-302, manufactured by Anton Paar).

◎: Viscosity at 3s-1 is 10 Pa・s or less. 〇: Viscosity at 3s-1 is less than 50 Pa・s. ×: Viscosity at 3s-1 is 50 Pa・s or more.

[Paste Stability Evaluation]
To 100 parts by weight of Ni powder (JFE Mineral: NFP201S), 10 parts by weight of barium titanate, 1 part by weight of dispersant, 3 parts by weight of ethyl cellulose (Dow, STD100), and 90 parts by weight of dihydroterpineol were added. The mixture was stirred using a planetary mixer, and then kneaded with a three-roll mill to obtain a Ni paste. The obtained paste was stored at 25°C, and the presence or absence of settling or separation of the paste was visually confirmed.

◎: No precipitation or separation of barium titanate was observed until the 28th.
○: No sedimentation or separation of barium titanate is observed for 7 days or more ×: Sedimentation or separation of barium titanate is observed within 7 days

As shown in Tables 2 and 3, in Examples 11 to 16 of the present invention, barium titanate dispersibility, nickel dispersibility, and paste stability were all good.

As shown in Table 4, the polymers of Comparative Examples 11 and 12 did not contain the monomer (A), but were poor in barium titanate dispersibility, nickel dispersibility and paste stability.
In the polymer of Comparative Example 13, a polycarboxylic acid-based polymer was used, but both the nickel dispersibility and the paste stability were low.
In the polymer of Comparative Example 14, a polyamine-based polymer was used, but both the dispersibility of barium titanate and the paste stability were low.
In the polymer of Comparative Example 15, a polycarboxylic acid polymer and a polyamine polymer were used in combination, but both the nickel dispersibility and the paste stability were low.

[Examples of Resist Resin Composition]
(Synthesis of Monomer A1)
Ethanol (Kishida Chemical Co., Ltd.), 50.0 g of gallic acid monohydrate (Tokyo Chemical Industry Co., Ltd.), and 2.4 g of triethylamine were charged into a 1 L flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel, and 51.3 g of glycidyl methacrylate (product name: Blenmar GH (NOF Corp.)) was added dropwise from the dropping funnel over 30 minutes, and the reaction was allowed to proceed at 80° C. for 10 hours. 100 g of butyl acetate (Kishida Chemical Co., Ltd.) was added to the reaction solution, which was then washed successively with a 0.1 M aqueous solution of sodium bicarbonate and saturated saline. The butyl acetate layer after washing was concentrated to obtain Monomer A1 having the structure shown in the following formula (3).

(Example 21)
A 1 L separable flask equipped with a stirrer, a thermometer, a condenser, a dropping funnel and a nitrogen inlet tube was charged with 350 g of propylene glycol monomethyl ether, and the atmosphere in the flask was replaced with nitrogen to create a nitrogen atmosphere. A monomer solution was prepared by mixing 18.3 g of Monomer A1, 7.6 g of methacrylic acid ("MAA Monomer" manufactured by Kuraray Co., Ltd.), and 74.1 g of cyclohexyl methacrylate ("Blenmer CHMA" manufactured by NOF Corporation), and a polymerization initiator solution was prepared by mixing 50 g of propylene glycol monomethyl ether and 6.3 g of 2,2'-azobis(2,4-dimethylvaleronitrile) (product name: V-65 (manufactured by Wako Pure Chemical Industries, Ltd.)).

The temperature inside the reaction vessel was raised to 75°C, and the monomer solution and the polymerization initiator solution were simultaneously dropped over 3 hours. After that, the mixture was reacted at 75°C for 3 hours to obtain a propylene glycol monomethyl ether solution of the resist resin of Example 21 (resin solids content 20%).

(Example 22)
A resist resin of Example 22 was obtained in the same manner as in Example 21, except that the monomer solution was changed to 26.7 g of Monomer A1, 12.3 g of acrylic acid ("Acrylic Acid" manufactured by Nippon Shokubai Co., Ltd.), 34.2 g of methyl methacrylate ("MMA Monomer" manufactured by Kuraray Co., Ltd.), and 26.6 g of styrene ("NS Styrene" manufactured by NS Styrene Monomer Co., Ltd.).

(Example 23)
A resist resin of Example 23 was obtained in the same manner as in Example 21, except that the monomer solution was changed to 47.0 g of Monomer A1, 6.5 g of methacrylic acid, and 46.5 g of cyclohexyl methacrylate.

(Example 24)
A resist resin of Example 24 was obtained in the same manner as in Example 21, except that the monomer solution was changed to 5.8 g of Monomer A1, 8.1 g of methacrylic acid, and 86.1 g of cyclohexyl methacrylate, and the amount of initiator in the polymerization initiator solution was changed to 3.0 g.

(Comparative Example 21)
A resist resin of Comparative Example 21 was obtained in the same manner as in Example 21, except that the monomer solution was changed to 5.8 g of acrylic acid, 40.2 g of methyl methacrylate, and 54.0 g of cyclohexyl methacrylate, and the amount of initiator in the polymerization initiator solution was changed to 3.0 g.

(Comparative Example 22)
A resist resin of Comparative Example 22 was obtained in the same manner as in Example 21, except that the monomer solution was changed to 12.9 g of methacrylic acid, 24.9 g of methyl methacrylate, and 62.2 g of styrene, and the amount of the initiator in the polymerization initiator solution was changed to 3.0 g.

[Measurement of weight average molecular weight]
The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) under the following conditions.
Apparatus: Tosoh Corporation, HLC-8220
Column: Shodex LF-804
Standard material: polystyrene Eluent: THF (tetrahydrofuran)
Flow rate: 1.0ml/min
Column temperature: 40°C
Detector: RI (Differential Refractive Index Detector)

[Evaluation of developability]
The resist resin solution was spin-coated on a silicon wafer and dried at 120°C to obtain a resin film with a thickness of 3 μm. The silicon wafer was immersed in a 1% aqueous sodium hydroxide solution for 30 seconds. The silicon wafer after immersion was visually observed to evaluate whether or not the polymer remained. When no resist resin remained, it was marked as "○", and when the resist resin remained, it was marked as "×".

[Evaluation of Room Temperature Adhesion]
The resist resin solution was applied to an alkaline glass plate using a bar coater, and dried for 5 minutes at 120° C. to obtain a resin film having a thickness of 5 μm. 100 squares were cut into the film, and Cellotape® (manufactured by Nichiban) was attached to the film. The Cellotape® was then peeled off, and the adhesion was evaluated based on the number of remaining squares and the appearance.
Those with no peeled squares and no chipped corners were rated as "O", those with no peeled squares but some chipped corners were rated as "△", and those with some peeled squares were rated as "X". The number of peeled squares was also counted, and the evaluation was made by dividing the number of peeled squares by the total number of squares.

[Appearance after high temperature and humidity conditions]
A diluted solution of 10 g of resist resin solution mixed with 10 g of propylene glycol monomethyl ether was applied to an alkaline glass using a bar coater, and dried at 120°C for 5 minutes to obtain a resin film with a thickness of 5 μm. This film was placed in a thermohygrostat (HASTEST PC-242HSR2 manufactured by Hirayama Seisakusho Co., Ltd.) set at a temperature of 100°C and a humidity of 100%, and left to stand for 2 hours. The appearance of the film after the high temperature and high humidity treatment was evaluated visually.

[Adhesion after high temperature and humidity conditions]
A diluted solution of 10 g of resist resin solution mixed with 10 g of propylene glycol monomethyl ether was applied to an alkaline glass using a bar coater, and dried at 120°C for 5 minutes to obtain a resin film with a thickness of 5 μm. This film was placed in a thermohygrostat (HASTEST PC-242HSR2 manufactured by Hirayama Seisakusho Co., Ltd.) set at a temperature of 100°C and a humidity of 100%, and left to stand for 3 hours. 100 squares were cut into the film after high temperature and high humidity treatment, cellophane tape (manufactured by Nichiban) was attached, the cellophane tape was peeled off, and the adhesion was evaluated by the number of squares and appearance.
Those with no peeled squares and no chipped corners were rated as "◎", those with no peeled squares but some with chipped corners were rated as "◯", and those with some peeled squares were rated as "X". The number of peeled squares was also counted, and the evaluation was performed by dividing the number of peeled squares by the total number of squares.

ＭＭＡ： メタクリル酸メチル
ＣＨＭＡ： メタクリル酸シクロヘキシル
ＡＡ： アクリル酸
ＭＡＡ： メタクリル酸
Ｓｔ： スチレン

MMA: Methyl methacrylate CHMA: Cyclohexyl methacrylate AA: Acrylic acid MAA: Methacrylic acid St: Styrene

ＭＭＡ： メタクリル酸メチル
ＣＨＭＡ： メタクリル酸シクロヘキシル
ＡＡ： アクリル酸
ＭＡＡ： メタクリル酸
Ｓｔ： スチレン

MMA: Methyl methacrylate CHMA: Cyclohexyl methacrylate AA: Acrylic acid MAA: Methacrylic acid St: Styrene

As shown in Table 5, the resist resin of the present invention can obtain a resin film with good adhesion even at room temperature and under high temperature and humidity conditions.

As shown in Table 6, the resist resin of Comparative Example 21 did not contain monomer (A), but the appearance and adhesion after high-temperature, high-humidity treatment were deteriorated. The resist resin of Comparative Example 22 did not contain monomer (A), but the appearance and adhesion after high-temperature, high-humidity treatment were deteriorated.

Claims (1)

An anticorrosive coating composition comprising a copolymer and an organic solvent,
The copolymer is a copolymer in which the molar ratio of the monomer (A) represented by the following general formula (1) is 1 to 99 mol %, the molar ratio of the (meth)acrylic acid alkyl ester (B) having 1 to 22 carbon atoms is 1 to 99 mol %, the molar ratio of the other copolymerizable monomer (C) is 0 to 98 mol %, and the weight average molecular weight is 3,000 to 1,000,000.

(In formula (1),
R is a hydrogen atom or a methyl group;
X represents an alkylene group having 2 to 5 carbon atoms or an alkylene group having 2 to 5 carbon atoms and one hydroxyl group.